1. Field of the Invention
The present invention relates to a fuel cell. In more detail, the present invention relates to a control technique during generation of electricity by a fuel cell which includes a plurality of stacks.
2. Description of the Related Art
With a fuel cell stack (in this specification, simply termed a “stack”) consisting of a plurality of cells stacked in layers, there is a tendency, in particular during starting, for rise of temperature to be delayed, the closer a cell is to the end portions of the stack. In this type of case, as a result of a state of oxygen shortage occurring at that site or the like, there is a fear that the output of the stack as a whole will decrease. In order to avoid a state in which the output decreases in this manner, there has been proposed a technique in which, for example during starting or the like, the cells at the end portions are eliminated, and electricity generation is performed with the remaining cells (for example, refer to Japanese Patent Application Publication 2005-183047).
However, if a plurality of such stacks are provided, since a method is adopted of flowing electric current through the cells at the end portions of the stacks in order to electrically connect them together, accordingly output decrease for the stack as a whole cannot be eliminated with this structure just as it is.